In the context of any country, which one of the following would be considered as part of its social capital ?

The correct answer is D. Social capital refers to the networks, norms of reciprocity and trust that let people cooperate for common ends. Putnam and Coleman built the idea around these features, and the level of mutual trust and harmony in a society is its clearest measure.

• A is wrong: Literacy is human capital, the skills and knowledge embodied in people. It is measured through education indicators, not through relationships.
• B is wrong: Buildings, infrastructure and machines are physical or produced capital, the core of the capital stock in national accounts.
• C is wrong: The working-age population is a demographic variable. It shapes the labour force and the possibility of a demographic dividend, but it says nothing about relationships between people.

For Mains, this links to GS-I (society, communalism, diversity) and GS-II (trust in institutions, community participation, and why governance works better where civic trust is high). Self-help groups and community policing both rely on social capital.

Trap: Candidates often lump literacy and health into 'capital' and pick A. Human capital and social capital are different categories, and the question asks only about relationships and trust.